Dustin Moskovitz, one of Facebook's cofounders, has sold off 450,000 shares of Facebook in the past week, according to a filing with the Securities and Exchange Commission via Bloomberg.

Moskovitz sold the shares between August 17-21 for between $19.38-$20 a share, the filing shows.

Moskovitz isn't the first Facebook insider to unload shares following the end of the company's first lockup period. Peter Thiel, an early investor in Facebook, raised eyebrows earlier this week for selling off 20 million shares.

Unlike Thiel though, Moskovitz is holding on to the majority of his stake in Facebook. He still has 7.05 million Class A shares.